Astronomers have found traces of a solar flare VII century BC

One of the most powerful geomagnetic storms on Earth have occurred in the year 660 BC, leaving prints in the ice cores and the rings of trees.

The powerful magnetic field of the Sun is never left alone. Ongoing active processes can lead to the appearance of coronal mass ejections: a flow of accelerated charged particles create instability in the solar wind and cause magnetic storms on Earth. These emissions can additionally accelerate the solar-wind protons to huge velocities. And if they usually do not penetrate through the earth’s magnetosphere, such proton bursts (Solar Proton Event SPE) may reach the ionosphere, disrupting satellite communications and causing auroras, according to the Chronicle.info with reference to naked-science.ru.

Until now, the mechanism of SPE-spikes need to be studied. Such events are quite rare, and modern observations of the Sun continued at least hundreds of years. Therefore, looking for their traces in the ancient samples: caused by the flow of protons interact in the atmosphere result in changes to the content of the different nuclides. Therefore, SPE may be affected in unexpected peak in the number included in the composition of plant carbon-14 in tree rings – or a peak content of beryllium-10 and chlorine-36 in ice cores.

In 2017, an international group of scientists drew attention to the carbon peak in tree rings corresponding to 660 BC, But it could well be the result of other events (for example, just a very powerful solar flare) – and researchers have continued to work. In a new article published in the journal Proceedings of the National Academy of Sciences, they added to this, the results of studies of ice.

Raymond Museler (Raimund Muscheler) from Lund University and his colleagues studied cores obtained from glaciers in Greenland. Indeed, in sediments, formed about the year 660 BC, the authors found a sharp increase in the content of rare isotopes of beryllium and chlorine, which confirms the version of events at that time a powerful burst of protons.

Scientists estimate that he was one of the strongest in the history of mankind – ten times more powerful than SPE a record of our time, was in 1956. Event 660 BC was only slightly weaker than the very strong surge, known to science, – the same dendrochronology and ice cores has allowed to date the 774-775 ad